Wood-fired pizza ovens release as much of a deadly pollutant into Bristol air every hour as hundreds of diesel cars

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• Phil Pope says:

  July 25, 2019 at 11:44 am

  This is slightly disingenuous. The PM standard for new diesels is 25 times lower than the original Euro1 standard in 1993. NEW diesels are required to meet the same PM standard as petrol cars. So why talk about diesel cars in the article? Because everyone knows OLD diesels and ones that cheated the emission tests gave out a lot more PM. So divide your 360 by the number of ovens and compare to old diesel rather than new and you get a headline – each woodfire oven emits less PM than an old diesel engine. Not great if you live next to a restaurant but not as alarming as you make out.

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  • Lorna says:

    July 30, 2019 at 12:38 pm

    Hi Phil, the comparison is based on DEFRA research, which specifically looked at Euro 6 diesel engines (linked in article).

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• Ben Woden says:

  July 25, 2019 at 1:45 pm

  “the same amount of deadly fine particulate air pollution into Bristol every hour as hundreds of diesel cars driving continuously”

  What does this mean? I don’t think it makes sense. You’re comparing an absolute amount with a rate. From later in the article, it seems like you mean the rate of emissions from the oven is 360x higher than the limit allowed for the car, but this isn’t clear from this first sentence, which doesn’t really make any sense at all.

  The amount emitted by the oven in one hour will be a quantity, say, 10mg (just for demonstration – I have no idea what the number is), but the amount emitted by a car “running continuously” won’t be an absolute amount like that, because no timeframe is defined – it’ll be something like 10mg/hr (again, totally made up number, but the important bit is the units). You can’t compare 10mg with 10mg/hr.

  Imagine that I said I could run as far as an hour as you can get by running continuously. That doesn’t make any sense. How far can you get “running continuously”? The question doesn’t make sense. Just as in the article, this example is trying to compare an absolute amount of something (distance in my example, rate in the article) with a rate. The two can’t be compared. You can’t say “which is longer, five miles or ten miles per hour?” It’s nonsensical as a question.

  I read on and it turns out that what you mean is probably that the oven emits 360x as fast as the car, or 360x as much in the same amount of time, but you really should change the first paragraph because it’s incredibly confusing, and bringing in “one hour” makes utterly no sense, because it makes it seem like you’re about to say the amount emitted by the ovens in one hour is 360x more than by the car in some amount of time, but then you don’t specify a time for the second point, and it just makes no sense.

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  • Lorna says:

    July 30, 2019 at 12:38 pm

    Hi Ben, the DEFRA research compares the emissions based on grammes per hour (g/h)

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• Matt Pascoe says:

  July 26, 2019 at 9:34 am

  I for one am glad that the world we live in is currently so peaceful that journalists have nothing more important to comment on than pizza ovens!

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• Deborah says:

  August 12, 2019 at 9:01 pm

  I am a little suspicious of the statistics which seem to support action on woodburning at the expense of reducing traffic. This is not really comparing like with like – woodburning produces higher levels of particulates but the primary issue with diesel is surely the N02 emissions? Happy to be corrected.

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